Critical seat selection and validation

Abstract

A method of assessing performance of a seat is provided. The method comprises identifying a number of critical seats for testing from a layout of passenger accommodation and building a computer simulation model, following a building block approach, for each identified critical seat. A number of loads are tested on each simulation model. Critical seats are selected for physical testing from simulation model test results according to a specified criteria assessment matrix.

What is claimed is: 
     
       1. A computer-implemented method of assessing performance of a seat, the method comprising:
 using one or more processors to perform the steps of: 
 identifying a number of critical seats designated for testing from a layout of passenger accommodation; 
 building a computer simulation model, following a building block approach, for each identified critical seat; 
 testing a number of loads on each simulation model; and 
 selecting critical seats for physical testing from simulation model test results according to a specified criteria assessment matrix, 
 wherein identifying critical seats further comprises: 
 identifying a number of seat families, wherein seats within a seat family comprise common or equivalent components in a primary load path; 
 identifying a number of baseline seats within each family, wherein each baseline seat comprises a unique configuration; and 
 analyzing interface loads and mounting cross-beams of the baseline seats to identify critical seats and cross-beams, wherein critical seats have weights above a first specified threshold and cross-beams have bending attributes above a second specified threshold. 
 
     
     
       2. The method of  claim 1 , further comprising:
 building a computer simulation model of a deployable airbag following a second building block approach; 
 testing performance of the airbag simulation model during a simulated deployment; and 
 evaluating airbag simulation model test results against physical test results of a counterpart airbag. 
 
     
     
       3. The method of  claim 2 , wherein the airbag is deployable from a bulkhead in front of an identified critical seat in the layout of passenger accommodation. 
     
     
       4. The method of  claim 2 , wherein testing deployment and performance of the airbag model comprises at least one of:
 time to firing; 
 volume and shape; 
 fold pattern; 
 deployment path; 
 venting and stiffness; or 
 tether to control airbag shape. 
 
     
     
       5. The method of  claim 2 , wherein the model of the deployable airbag is built according to a number of criteria including at least one of:
 regulatory requirements; 
 occupant restraint protocol; 
 occupant coverage; 
 proximity of the airbag to a feature in an aircraft interior; 
 time to firing; 
 accelerometers and locations; or 
 inflator mass flow. 
 
     
     
       6. The method of  claim 1 , further comprising:
 grouping seats within each family by number of legs; 
 sub-grouping seats within each family group by lateral leg spacing; and 
 sub-grouping seats within each family group by seat leg pitch. 
 
     
     
       7. The method of  claim 1 , wherein analyzing interface loads and mounting cross-beams of the baseline seats comprises analyzing load forward and down conditions for different occupancy conditions including fully occupied, partially occupied, and unoccupied. 
     
     
       8. The method of  claim 1 , wherein analyzing interface loads and mounting cross-beams of the baseline seats comprises removing from consideration non-critical parts with static loads below a specified threshold. 
     
     
       9. The method of  claim 1 , wherein testing loads on each simulation model includes loads of:
 14 g down; and 
 16 g forward. 
 
     
     
       10. The method of  claim 1 , wherein the criteria assessment matrix relates a number of test cases to a number of structural seat criteria and a number of occupant safety criteria. 
     
     
       11. The method of  claim 10 , wherein the structural seat criteria comprise at least one of:
 floor reaction loads; 
 seatbelt attachment loads; 
 structural deformation; 
 critical strains; 
 von Mises stresses; or 
 track fitting interface shear stress. 
 
     
     
       12. The method of  claim 10 , wherein the occupant safety criteria comprise at least one of:
 head path; 
 head displacement, velocity, and acceleration, 
 head injury criteria; 
 oblique neck injury criteria; 
 lumbar forces; 
 pelvic acceleration; or 
 femur loads. 
 
     
     
       13. The method of  claim 1 , wherein building the computer simulation model for each identified critical seat further comprises:
 modeling a number of materials comprising the seat; 
 evaluating material model predictions against physical test results of counterpart materials; 
 modeling joints between a number of components comprising the seat; 
 evaluating joint model predictions against physical test results of counterpart joints; 
 modeling each component comprising the seat, including properties of materials comprising each component; 
 evaluating component model predictions against physical test results of counterpart components; 
 modeling a number of sub-systems of the seat, wherein each sub-system comprises a portion of the components comprising the seat, including joints between components; 
 evaluating sub-system model predictions against physical test results of counterpart sub-systems; and 
 modeling the seat. 
 
     
     
       14. The method of  claim 13 , wherein the properties of materials comprising seat components comprise at least one of:
 Young's modulus; 
 Poisson's ratio yield strength; 
 ultimate strength; 
 shear; 
 bearing; 
 elongation; 
 displacement; or 
 density. 
 
     
     
       15. The method of  claim 13 , wherein modeling is performed for one or more of the following components:
 seat track; 
 seat fitting to the seat track, including stud and shear plunger; 
 bottom cushions; 
 back cushions; 
 seatbelt; 
 shackles; 
 discrete energy absorbers; or 
 seat components in a primary load path. 
 
     
     
       16. The method of  claim 13 , wherein modeling is performed for one or more of the following sub-systems:
 lower structure including legs, cross-tubes, seat pans, and spreaders; 
 upper structure including seat back and seatback control mechanism; 
 seat cushions including bottom and back cushions; 
 restraint system including seatbelt and shackles; or 
 items of mass including tray table and footrest. 
 
     
     
       17. The method of  claim 1 , wherein testing loads on each simulation model further comprises:
 defining a model to be analyzed; 
 specifying an intended use of the model and a scope of analysis; 
 determining a number of data requirements for the simulation; and 
 preparing a model interface setup comprising integration of the seat model, a virtual anthropomorphic test device, seat track, and floor deformation fixtures. 
 
     
     
       18. The method of  claim 1 , further comprising evaluating simulation model test results for:
 energy balance; 
 mass and moment of inertia; 
 penetration check; 
 virtual anthropomorphic test device kinematic evaluation; and 
 floor interface load check. 
 
     
     
       19. The method of  claim 1 , further comprising:
 comparing simulation model test results of each selected critical seat to physical test results of a counterpart seat; and 
 determining if the seat models reproduce the same behavior as equivalent physical seats within specified error limits. 
 
     
     
       20. The method of  claim 19 , further comprising:
 evaluating a virtual anthropomorphic test device; 
 evaluating seat structural response; and 
 evaluating an assembly of the virtual anthropomorphic test device and seat. 
 
     
     
       21. A system for assessing performance of a seat, the system comprising:
 a storage device configured to store program instructions; and 
 one or more processors operably connected to the storage device and configured to execute the program instructions to cause the system to:
 identify a number of critical seats designated for testing from a layout of passenger accommodation; 
 build a computer simulation model, following a building block approach, for each identified critical seat; 
 test a number of loads on each simulation model; and 
 select critical seats for physical testing from simulation model test results according to a specified criteria assessment matrix, 
 
 wherein identifying critical seats further comprises:
 identifying a number of seat families, wherein seats within a seat family comprise common or equivalent components in a primary load path; 
 identifying a number of baseline seats within each family, wherein each baseline seat comprises a unique configuration; and 
 analyzing interface loads and mounting cross-beams of the baseline seats to identify critical seats and cross-beams, wherein critical seats have weights above a first specified threshold and cross-beams have bending attributes above a second specified threshold. 
 
 
     
     
       22. The system of  claim 21 , further comprising:
 building a computer simulation model of a deployable airbag following a second building block approach; 
 testing performance of the airbag simulation model during a simulated deployment; and 
 evaluating airbag simulation model test results against physical test results of a counterpart airbag. 
 
     
     
       23. The system of  claim 22 , wherein the airbag is deployable from a bulkhead in front of an identified critical seat in the layout of passenger accommodation. 
     
     
       24. The system of  claim 22 , wherein testing deployment and performance of the airbag model comprises at least one of:
 time to firing; 
 volume and shape; 
 fold pattern; 
 deployment path; 
 venting and stiffness; or 
 tether to control airbag shape. 
 
     
     
       25. The system of  claim 22 , wherein the model of the deployable airbag is built according to a number of criteria including at least one of:
 regulatory requirements; 
 occupant restraint protocol; 
 occupant coverage; 
 proximity of the airbag to a feature in an aircraft interior; 
 time to firing; 
 accelerometers and locations; or 
 inflator mass flow. 
 
     
     
       26. The system of  claim 21 , further comprising:
 grouping seats within each family by number of legs; 
 sub-grouping seats within each family group by lateral leg spacing; and 
 sub-grouping seats within each family group by seat leg pitch. 
 
     
     
       27. The system of  claim 21 , wherein analyzing interface loads and mounting cross-beams of the baseline seats comprises analyzing load forward and down conditions for different occupancy conditions including fully occupied, partially occupied, and unoccupied. 
     
     
       28. The system of  claim 21 , wherein analyzing interface loads and mounting cross-beams of the baseline seats comprises removing from consideration non-critical parts with static loads below a specified threshold. 
     
     
       29. The system of  claim 21 , wherein testing loads on each simulation model includes loads of:
 14 g down; and 
 16 g forward. 
 
     
     
       30. The system of  claim 21 , wherein the criteria assessment matrix relates a number of test cases to a number of structural seat criteria and a number of occupant safety criteria. 
     
     
       31. The system of  claim 30 , wherein the structural seat criteria comprise at least one of:
 floor reaction loads; 
 seatbelt attachment loads; 
 structural deformation; 
 critical strains; 
 von Mises stresses; or 
 track fitting interface shear stress. 
 
     
     
       32. The system of  claim 30 , wherein the occupant safety criteria comprise at least one of:
 head path; 
 head displacement, velocity, and acceleration, 
 head injury criteria; 
 oblique neck injury criteria; 
 lumbar forces; 
 pelvic acceleration; or 
 femur loads. 
 
     
     
       33. The system of  claim 21 , wherein building the computer simulation model for each identified critical seat further comprises:
 modeling a number of materials comprising the seat; 
 evaluating material model predictions against physical test results of counterpart materials; 
 modeling joints between a number of components comprising the seat; 
 evaluating joint model predictions against physical test results of counterpart joints; 
 modeling each component comprising the seat, including properties of materials comprising each component; 
 evaluating component model predictions against physical test results of counterpart components; 
 modeling a number of sub-systems of the seat, wherein each sub-system comprises a portion of the components comprising the seat, including joints between components; 
 evaluating sub-system model predictions against physical test results of counterpart sub-systems; and 
 modeling the seat. 
 
     
     
       34. The system of  claim 33 , wherein the properties of materials comprising seat components comprise at least one of:
 Young's modulus; 
 Poisson's ratio 
 yield strength; 
 ultimate strength; 
 shear; 
 bearing; 
 elongation; 
 displacement; or 
 density. 
 
     
     
       35. The system of  claim 33 , wherein modeling is performed for one or more of the following components:
 seat track; 
 seat fitting to the seat track, including stud and shear plunger; 
 bottom cushions; 
 back cushions; 
 seatbelt; 
 shackles; 
 discrete energy absorbers; or 
 seat components in a primary load path. 
 
     
     
       36. The system of  claim 33 , wherein modeling is performed for one or more of the following sub-systems:
 lower structure including legs, cross-tubes, seat pans, and spreaders; 
 upper structure including seat back and seatback control mechanism; 
 seat cushions including bottom and back cushions; 
 restraint system including seatbelt and shackles; or 
 items of mass including tray table and footrest. 
 
     
     
       37. The system of  claim 21 , wherein testing loads on each simulation model further comprises:
 defining a finite element model to be analyzed; 
 specifying an intended use of the model and a scope of analysis; 
 determining a number of data requirements for the simulation; and 
 preparing a model interface setup comprising integration of the finite element model, a virtual anthropomorphic test device, seat track, and floor deformation fixtures. 
 
     
     
       38. The system of  claim 21 , further comprising evaluating simulation model test results for:
 energy balance; 
 mass and moment of inertia; 
 penetration check; 
 virtual anthropomorphic test device kinematic evaluation; and 
 floor interface load check. 
 
     
     
       39. The system of  claim 21 , further comprising:
 comparing simulation model test results of each selected critical seat to physical test results of a counterpart seat; and 
 determining if the seat models reproduce the same behavior as equivalent physical seats within specified error limits. 
 
     
     
       40. The system of  claim 39 , further comprising:
 evaluating a virtual anthropomorphic test device; 
 evaluating seat structural response; and 
 evaluating an assembly of the virtual anthropomorphic test device and seat. 
 
     
     
       41. A computer program product for seat certification for aircraft under emergency landing dynamic loading conditions, the computer program product comprising:
 a non-transitory computer readable storage media having program instructions embodied therewith, the program instructions executable by a number of processors to cause a number of processors to perform the steps of:
 identifying a number of critical seats designated for testing from a layout of passenger accommodation; 
 building a computer simulation model, following a building block approach, for each identified critical seat; 
 testing a number of loads on each simulation model; and 
 selecting critical seats for physical testing from simulation model test results according to a specified criteria assessment matrix, 
 wherein identifying critical seats further comprises:
 identifying a number of seat families, wherein seats within a seat family comprise common or equivalent components in a primary load path; 
 identifying a number of baseline seats within each family, wherein each baseline seat comprises a unique configuration; and 
 analyzing interface loads and mounting cross-beams of the baseline seats to identify critical seats and cross-beams, wherein critical seats have weights above a first specified threshold and cross-beams have bending attributes above a second specified threshold. 
 
 
 
     
     
       42. A computer-implemented method of assessing performance of a seat, the method comprising:
 using one or more processors to perform the steps of: 
 identifying a number of critical seats designated for testing from a layout of passenger accommodation; 
 building a computer simulation model, following a building block approach, for each identified critical seat; 
 testing a number of loads on each simulation model; 
 selecting critical seats for physical testing from simulation model test results according to a specified criteria assessment matrix; 
 building a computer simulation model of a deployable airbag following a second building block approach; 
 testing performance of the airbag simulation model during a simulated deployment; and 
 evaluating airbag simulation model test results against physical test results of a counterpart airbag, 
 
       wherein building the simulation model of the deployable airbag comprises:
 modeling a number of materials comprising the deployable airbag; 
 evaluating material model predictions against physical test results of counterpart materials; 
 modeling folding and packaging of the airbag; 
 evaluating folding and packaging model predictions against physical test results of counterpart folding and packaging; 
 modeling each component comprising the deployable airbag, including properties of materials comprising each component; 
 evaluating component model predictions against physical test results of counterpart components; 
 modeling a number of sub-systems of the deployable airbag, wherein each sub-system comprises a number of the components comprising the deployable airbag; 
 evaluating sub-system model predictions against physical test results of counterpart sub-systems; and 
 modeling the deployable airbag. 
 
     
     
       43. A system for assessing performance of a seat, the system comprising:
 a storage device configured to store program instructions; and 
 one or more processors operably connected to the storage device and configured to execute the program instructions to cause the system to:
 identify a number of critical seats designated for testing from a layout of passenger accommodation; 
 build a computer simulation model, following a building block approach, for each identified critical seat; 
 test a number of loads on each simulation model; 
 select critical seats for physical testing from simulation model test results according to a specified criteria assessment matrix; 
 building a computer simulation model of a deployable airbag following a second building block approach; 
 testing performance of the airbag simulation model during a simulated deployment; and 
 evaluating airbag simulation model test results against physical test results of a counterpart airbag, 
 
 
       wherein building the simulation model of the deployable airbag comprises:
 modeling a number of materials comprising the deployable airbag; 
 evaluating material model predictions against physical test results of counterpart materials; 
 modeling folding and packaging of the airbag; 
 evaluating folding and packaging model predictions against physical test results of counterpart folding and packaging; 
 modeling each component comprising the deployable airbag, including properties of materials comprising each component; 
 evaluating component model predictions against physical test results of counterpart components; 
 modeling a number of sub-systems of the deployable airbag, wherein each sub-system comprises a number of the components comprising the deployable airbag; 
 evaluating sub-system model predictions against physical test results of counterpart sub-systems; and 
 
       modeling the deployable airbag. 
     
     
       44. A computer program product for seat certification for aircraft under emergency landing dynamic loading conditions, the computer program product comprising:
 a non-transitory computer readable storage media having program instructions embodied therewith, the program instructions executable by a number of processors to cause a number of processors to perform the steps of:
 identifying a number of critical seats designated for testing from a layout of passenger accommodation; 
 building a computer simulation model, following a building block approach, for each identified critical seat; 
 testing a number of loads on each simulation model; and 
 selecting critical seats for physical testing from simulation model test results according to a specified criteria assessment matrix; 
 building a computer simulation model of a deployable airbag following a second building block approach; 
 testing performance of the airbag simulation model during a simulated deployment; and 
 evaluating airbag simulation model test results against physical test results of a counterpart airbag, 
 
 wherein building the simulation model of the deployable airbag comprises:
 modeling a number of materials comprising the deployable airbag; 
 evaluating material model predictions against physical test results of counterpart materials; 
 modeling folding and packaging of the airbag; 
 evaluating folding and packaging model predictions against physical test results of counterpart folding and packaging; 
 modeling each component comprising the deployable airbag, including properties of materials comprising each component; 
 evaluating component model predictions against physical test results of counterpart components; 
 modeling a number of sub-systems of the deployable airbag, wherein each sub-system comprises a number of the components comprising the deployable airbag; 
 evaluating sub-system model predictions against physical test results of counterpart sub-systems; and 
 modeling the deployable airbag.